The redirection of the thematic areas at the AECOM CFAR to immune-based therapeutic and preventive agendas has mandated in 1990 the conversion of the original hybridoma core into an immunology/vaccine core. This new core standardizes a wide array of immunology markers in the context of antiviral and immune based interventions targeted at manifestation of host defense mechanisms in order to prevent infection or improve outcome. The core will provide access to otherwise unobtainable research capabilities in two major categories critical for the CFAR's progress: (a) Immunological surrogate markers, such as neopterin, Beta2, TNFalpha, sCD8. (b) HIV specific assays targeted to variety of epitopes, but currently focused on gp120 and in the V3 loop primary neutralizing domain (PND) (i) Humoral immune response: serum and secretory IgA (purified at the core) will be assessed for PND reactivity, PND high affinity/avidity cross reactivity; PND and IgG-subclass specific antibodies. (ii) Cellular immunity: Antigen (PND;gp120) driven lymphocyte proliferation, secretion of IL2;IL4;IL10; and specific CTLs of PBMC and sorted cells. This core will be highly interactive with other cores, but more so with the FACS and virology cores. The Core Director will continuously assess the needs for incorporation of new promising immunological assays critical in advancing the common goals of the CFAR and the AECOM-AIDS research agenda. He will be responsible to keep CFAR investigators abreast of new developments in core capabilities and enrich those by interaction with the CFAR committees, the EAC and through visiting scientists/consultants.